Metalclad switchgear using vacuum interrupter elements

ABSTRACT

A circuit breaker for metalclad switchgear use is provided using vacuum-interrupter elements in substitution of the usually provided magnetic and insulating plate structures, customarily employed. A resilient mounting for the interrupter elements is provided, together with massive end contact blocks for heat dissipation generated within the vacuum-interrupter elements. A pivoted operating lever, connected to the massive contact block secured to the moving contact of the vacuum-interrupter, is operated by a resilient connection to the insulating operating rod of the circuit breaker. Because of the reduced dimensions, the cubicle dimensions may be drastically reduced, if desired.

United States Patent (72] Inventor Russell E. Frlnk Forest Hllls,Plttsburgh, Pa.

(2H Appl. No. 709,013

[22] Filed Feb. 28, I968 [45] Patented Sept. 7, I97] 1 73 I AnsigneeWestlnghouse Electric Corporation Pittsburgh, Pa.

[54] METALCLAD SWITCHGEAR USING VACUUM INTERRUPTER ELEMENTS 8 Claims, 6Drawing Figs.

{52] US. Cl 200/[44 B, 200/50 AA {51] lnLCL .i...H0lh33/66 [50] Field atSearch 200/50 AA, [44 B [56] References Cited UNITED STATES PATENTS3,30S 65 7 2/l967 Roxburgh et al. 200/5015 X 3,397,293 8/1968 Darrow et200/5015 FOREIGN PATENTS l,260,754 4/I96l France a, 200150.15

966,538 9/1967 Germany 200/50. l 5

Primary Examiner Robe rt St Macon Attorneys-A. T. Stratton. Clement L.McHale and Willard R,

Crout ABSTRACT: A circuit breaker for metalclad switchgear use isprovided using vacuuminterrupter elements in substitution of the usuallyprovided magnetic and insulating plate structures. customarily employedA resilient mounting for the inter rupter elements is provided, togetherwith massive end con tact blocks for heat dissipation generated withinthe vacuuminterrupter elements. A pivoted operating lever, connected tothe massive contact block secured to the moving contact of thevacuum-interrupter, is operated by a resilient connection to theinsulating operating rod of the circuit breaker. Because of the reduceddimensions, the cubicle dimensions may be drastically reduced, ifdesired.

PATENTEB SEP 7 ISH SHEET 2 0F 3 FIG.3.

PATENTEUSEP 7l97i 3503753 SHEEI 3 [1F 3 i iL.JL.J 50 CONTROL, r MODULE jL1 V CONTROL I MODULE r 5 s| L T I I I l BREAKER- I AND LINE BUS lMODULE --9 6 MODULE I: 1 j H I L I fifiofifiE \LINE PRI A T PRIQR RTMODULE FIGS.

FIG.4.

s2 L l L Q I I l BREAKER I LINE fi s MODULE MODULE i j 1 I l i iHLBREAKER AND BUS MODULE LINE MODULE FIG.6.

METALCLAD SWITCIIGEAR USING VACUUM INTERRUPTER ELEMENTS CROSS-REFERENCESTO RELATED APPLICATIONS Applicant is not aware of any related patentapplications pertinent to the present invention.

BACKGROUND OF TH E INV ENTION As well known by those skilled in the artmetalclad switchgear his achieved extensive use within the industry.Customarily, magnetic air-break arc-chute structures have been employed,such as set forth in U.S. Pat. 3,307,004, issued Feb. 28, 1967, toSamuel A Bottonari, and assigned to the assignee of the instantapplication. Such magnetic air-break circuit interrupters are rolled ona movable truck into a cubicle, or metalclad switchgear enclosure, foreither indoor or outdoor use, and the surrounding grounded housingprovides protection to operating personnel.

Vacuum-type circuit interrupters have developed, and are, at the presenttime, of considerable reliability. It is desirable, therefore, toutilize the new type vacuum-interrupter units, of proven integrity, inthe metalclad switchgear industry to take advantage of their small sizeand efficient operation.

It is, accordingly, an object of the present invention to utilize theimproved construction of present-day vacuum-interrupter units withinmetalclad switchgear, and to provide the requisite additional componentsto render their operation reliable and trouble-free.

SUMMARY OF THE INVENTION According to a preferred embodiment of thepresent invention, there is provided a truck-mounted switchgear unitincorporating vacuum-type interrupter elements so that a threephaseinterrupter may be rolled into the cubicle, or metalclad switchgearhousing, with the mounting being sufficiently resilient, and provisionmade for heat conduction from within the interior of thevacuum-interrupter envelopes, so that reliable operation is achieved.According to the invention, the interrupter elements are resilientlysupported by a plurality of conducting straps constituting leaf springs,and heat conduction from the evacuated interior of the interrupterelements is transmitted by the utilization of relatively massive splitcontact blocks clamped to the vacuum-interrupter contacts, so thatreliable operation is achieved at a relatively low tempera ture.

A contact finger arrangement is used to achieve current conductionbetween the contact block, clamped to the movable contact rod, and theterminal-bushing termination with contact finger springs so supplied asto efi'ect both adequate contact pressure at the termination, and alsoat the movable contact block secured to the moving contact rod of thevacuum interrupter element.

It is, accordingly, a general object of the present invention to providean improved metalclad switchgear structure utilizing vacuum-interrupterelements in place of the customarily provided magnetic air-break arcchutes.

Still a further object of the present invention is the provision of animproved vacuum-type circuit breaker in which provision is made for aresilient and flexible mounting of the vacuuminterrupter elements, andalso provision is additionally provided for the heat generated withinthe vacuum-interrupted units during circuit interruption.

Still a further object of the present invention is the provision of animproved current-transfer arrangement between the moving contact of thevacuum-interrupter and the terminal of the associated bushing structure.

Another object of the present invention is the provision of an improvedresilient mounting for a vacuum-interrupter unit utilizing a novelresilient contact compression spring between the insulating operatingrod and the pivoted actuating lever for the movable contact rod of thevacuum-interrupter.

Yet a further object of the present invention is the provision of animproved resilient mounting for a vacuum-interrupter unit to lower theimpact forces encountered during the opening and closing operations by amultiple-leaf spring construction, without unnecessarily increasing thenumber of com ponent parts associated with the vacuum-type circuitinterrupter.

Further objects and advantages will readily become apparent upon readingthe following specification, taken in con' junction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of atruck-mounted mctalclad type of switchgear breaker incorporatingvacuum-type inter rupting elements, with the breaker shown in the closedcircuit position;

FIG. 2 is an enlarged fragmentary side elevational view, par tially invertical section, of the vacuum-type switchgear structure of FIG. I, thecontacts being illustrated in the opencircuit position;

FIG. 3 is an enlarged side elevational view of the resilient mountingfor the vacuum-interrupter element, together with a showing of theresilient interconnection between the operating rod and the pivotedoperating lever, the contact structure being illustrated in theclosed-circuit position;

FIG. 4 is a diagrammatic view of a prior art type of metalcladswitchgear structure using magnetic air-type arc chutes, andillustrating the space required, with the circuit breaker beingindicated in the operating and test positions;

FIG. 5 is a perspective view of a prior art type of metalclad switchgearstructure illustrating the considerable space required; and,

FIG. 6 is a diagrammatic view illustrating the saving contact fingerspace obtained by the use of vacuum-interrupter elements in place of thecustomarily employed magnetic-type arc-chute structures.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, andmore particularly to FIG. 1 thereof, the reference numeral I generallydesignates a truck mounted three-phase metalclad type of circuitbreaker. As shown, the three-phase circuit-interrupter unit comprisesthree vacuum-type circuit-interrupter elements 2, 3 and 4 positionedgenerally vertically between pairs of horizontally extending terminalbushings 5, 6 the latter being supported by insulating pole supports 7.The pole supports 7 may be formed of porcelain, as set forth anddescribed in U.S. Pat. applica tion, Ser. No. 433,529, filed Jan. 26,l965, by James R. Gamble, entitled Joint Constructions," and assigned tothe assignee of the instant application.

It will be noted that the three insulating pole supports 7 are bolted,as at 8, to a lower metallic frame support 9, mounted upon wheels 10,and adaptable for insertion and withdrawal within metalclad switchgearcell structure I], as illustrated in FIGS. 5 and 6 of the drawings. Asolenoid-operating mechanism, or a stored-energy operating mechanism I3may be provided within the lower framework 9 of the circuit breaker l,the construction of which constitutes no part of the present invention.Reference may be had to U.S. Pat 3,183,332 issued May 22, l965 to Funket al. for a typical stored-energy operating mechanism 13, which may beu used, ifdesired,

FIG, 2 more clearly illustrates the internal construction of thevacuum-interrupter elements, showing the separable con tacts l4, 15 theupper contact 14 being a stationary contact and supported upon astationary contact rod I6 extending upwardly through the upper end 17 ofthe vacuum interrupter element and clamped within a relatively massivecontact block 18. Clamping bolts I9 may be employed to effect a secureclamping engagement between the contact block 18 and the stationarycontact rod extension I6. As shown, the relatively massive split contactblock I8 is secured, as by brazing,

between a pair of laterally extending contact straps 20, 21, which, forexample, may be made of hard copper or chrome copper, so as to besomewhat resilient. The lower contact strip 21 may have aperturesprovided therethrough to accommodate mounting studs 22, which may beprovided by the manufacturer of the vacuum-interrupter element.Consequently, the mounting nuts 23, secured to the interrupter elementmounting studs 22, if provided, together with the secure clamping of thecontact block I8 to the upper end portion of the stationary contact rod[6, provides a secure attachment of the interrupter element to theterminal 24 of the upper terminal bushing 25, the latter extendingthrough the upper end of the insulating pole support 7.

In vacuum-type circuit interrupters, there is no internal convectivecooling; and cooling by radiation is very slight because the metalcondensing shield 26 also acts as a radiation shield. This means thatpractically all of the heat generated interiorly of thevacuum-interrupter element must be taken out through the terminals anddissipated externally. The provision of the relatively massive splitcontact block 18, which may be of copper, adequately provides a heatsink for the storage of heat generated within the vacuum interrupterelement.

The lower terminal bushing 27 has a terminal member, designated by thereference numeral 28, and to this is bolted, as at 29, a wide flatsupporting member 30, made of a conducting resilient material, such assilicon bronze, for example. As shown in FIG. 3, the fiat support member30 may be secured to the vacuum-interrupter element by mounting studs 3!supplied with the interrupter element by the manufacturer, and thesemounting studs 3I may extend through registering apertures provided inthe flat supporting strip 30 and secured thereto by suitable mountingnuts 32.

The vacuum-interrupter element itself has simple butt con tacts I4, I5,and they are closed at high speeds. In order to reduce the rebound ofthese contacts, a certain amount of resiliency must be provided in theinterrupter mounting. It will be noticed, in this connection, that theelements 20, 21, and 30 act as leaf springs to provide this resiliency.

Bolted to the lower movable contact rod 33 of the vacuumtype interrupterelement 4, which moves in a reciprocally vertical direction, is a splitrelatively massive contact block 34, which is conductively connected tothe lower bushing foot, or terminal 35, by a multiplicity of contactfingers 36. Contact pressure between these contact fingers 36 and thecontact block 34 and end terminal 35 of the bushing 27 is provided bycompression springs 37 The interrupting device, as shown in FIG. 3, isin the closed position, and operation between the open and closedpositions is effected by the bifurcated operating lever 38. Theoperating lever 38 is pivoted about a fixed support pin 39, and isconnected to the contact lock 34, and moving contact rod 33 by themoving pin 40. The end of the operating lever 38 is rotatably operatedby the insulating operating rod 42. In the closed position, as shown inFIG. 3, the insulating rod 42 has compressed the contact compressionsprings 43, which bias the operating lever 38 in a counterclockwisedirection about the fixed mounting pin 39, and, through the pin 40,holds the interrupter contacts I4, I closed with the required force.

When the circuit breaker mechanism 13 is tripped, the insulatingoperating rod 42 moves downwardly gathering momen' tum, until the nut 44at its upper extremity strikes the top 380 of the forked operating lever38. This opens the interrupter contacts with an impact force, whichbreaks loose any welds, which may have formed and separates the contacts14, IS with an initial velocity. The travel of the insulating operatingrod 42 is stopped when the required contact separation is reached.During the closing operation, the operating rod 42 is moved upwardly,and the butt contacts within the interrupter strike together with animpact, which is cushioned by the resiliency of the leaf members 20, ZIand 3t) and by the contact compression spring 43. The operating rod 42continues to move until it reaches the position shown in FIG. 3.

FIGS. 4 and 5 diagrammatically illustrate a conventional magneticair-break circuit interrupter, and the necessity for providing adequatespace for the exhaust gases generated within the magnetic-type air-breakarc chute 46. Reference may be had to U.S. Pat. 3,307,004 for a typicalarc-chute structure. Also reference may be had to U.S. Pat. applicationfiled July ll, I967 Ser. No. 652,526 by Samuel A. Bottonari, now U.S.Pat. No. 3,538,279 issued Nov. 3, I970 assignee of the instantapplication, for a description of a typical type of air-break arc chutestructure 46, and the description of the concomitantly generatedarc-chute gases. Provision must be made, of course, for the cooling ofsuch generated gases; and the space 48 in FIG. 4 is requisite for suchaccommodation.

It will be noted, however, that due to the small size of the interrupterelements 2, 3, 4, and the fact that no exhaust gases are generated,leads to drastically reduced dimensions. FIG. 6 illustrates an outlineof the circuit breaker of the present invention as positioned within ametalclad cell 11. With a conventional type of magnetic air-breakcircuit interrupter 46, the breaker completely fills the space, andexpansion space for the exhaust gases is provided for in the controlmodule 50 (FIG. 5), which is mounted on top of the breaker module SIvThe vacuum breaker, however, is considerably smaller thin a conventional type of magnetic air-break circuit interrupter 46, and surplusspace 52, as shown by the crosshatched area, is available to be used forinstruments and control. This eliminates the necessity for providing acontrol module 50, such as illustrated in FIG. 5, and results in asubstantial cost improvement.

If it is desired to make the vacuum breakers of the present inventioninterchangeable with olderstyle magnetic air-break circuit interrupters,such as the type known as DH-P," it is only necessary to equip thevacuum breaker with an in' terphase barrier of the same physical size asthat used for the type 5H4 breakers, and provide standard DH-P cells.The breakers are then perfectly interchangeable.

From the foregoing description it will be apparent that there has beenprovided an improved metalclad type of switchgear utilizing vacuum-typeinterrupter elements 2, 3, 4 in place of the ordinarily utilizedmagnetic-type air-break arc-chute structures 46. In addition, aresilient mounting 54 for such vacuum interrupter elements has beensupplied by the use ola leaf-spring construction, and the dissipation ofheat generated within the vacuum interrupter envelopes has been providedby the use of heat sinks S5, or relatively massive contact blocks 18,34, which are secured to the stationary and movable con tact elements ofthe vacuumtype circuit interrupter.

It will, additionally, be noted that a relatively simple contact fingerarrangement 36 has been provided between the lower movable contact block34 and the terminal-bushing end terminal member 35 by a relativelysimple contact finger construction 36 suitably biased by contactcompression springs 37. Finally, the interposition of the contactcompression springs 43 between the movable operating rod 42 and themovable operating lever 38 provide a desired resilient and cushioningaction during the closing operation with the additional provision of ashock opening force during the opening operation to break any welds,which may have formed between the separable contacts I4, 15.

Although there has been illustrated and described a specific structure,it is to be clearly understood that the same was mereiy for the purposeof illustration, and that changes and modifications may readily be madetherein by those skilled in the art, without departing from the spiritand scope of the invention.

I claim:

1. A truck-mounted multipole vacuum-type circuit interrupter including,in combination:

a. a wheeled truck carrying a plurality of side-byside verticallydisposed vacuum-interrupter units;

bv the upper and lower terminal ends of each vertically disposedvacuum-interrupter unit being electrically con nected to upper and lowerspaced horizontally disposed terminal bushings,

the truck additionally carrying an operating mechanism for thesimultaneous operation of all the vertically disposed vacuum'typeinterrupter units; and,

a flexible mounting means being provided for each vacuumtype interrupterunit including at least one flexible conducting strap interposed betweenthe terminal of one of the terminal bushing for each unit and one of theends of said respective unit.

2. The truck-mounted multipole vacuum-type circuit interrupter ofclaim1, including;

a pivotally mounted operating lever connected to the movable verticallyactuable contact of each vacuum-interrupter unit; and,

an insulating operating rod mechanically connected between the free endof the respective operating lever and the operating mechanism.

3. The combination according to claim 1 wherein each vacuumtypecircuit-interrupter element includes a pair of separable contactsseparated within an evacuated enclosure, at least one contact rodsupporting one of said contacts extending externally of the evacuatedenclosure, and a heat sink comprising a relatively massive contact blocksecured to the external end of said contact rod.

4. The combination according to claim 3, wherein the contact block issplit and adapted for clamping action.

5. The combination according to claim I, wherein the flexible mountingmeans includes a plurality of laterally extending flexible conductingstraps interposed between the terminals ol the two terminal bushings ofeach interrupter unit and the ends of said respective interrupter unit.

6. At the combination according to claim 1, wherein each vacuum-typecircuit interrupter element includes a pair of separable contactsseparated within an evacuated enclosure. stationary and movable contactrods extending externally of the evacuated enclosure, and a pair of heatsinks comprising relatively massive contact blocks secured to theexternal ends of said contact rods.

7. The combination according to claim I, wherein the upper end of eachof the vacuum-type interrupter units includes as a part of said flexiblemounting means a pair of laterally extending flexible conducting strapsextending between the upper end of the respective unit and the terminalof the upper terminal bushing for said respective unit.

8. The combination according to claim 3, wherein the flexible mountingmeans for each unit includes a pair of straps disposed on opposite sidesof said heat sink.

1. A truck-mounted multipole vacuum-type circuit interrupter including,in combination: a. a wheeled truck carrying a plurality of side-by-sidevertically disposed vacuum-interrupter units; b. the upper and lowerterminal ends of each vertically disposed vacuum-interrupter unit beingelectrically connected to upper and lower spaced horizontally disposedterminal bushings; the truck additionally carrying an operatingmechanism for the simultaneous operation of all the vertically disposedvacuumtype interrupter units; and, a flexible mounting means beingprovided for each vacuum-type interrupter unit including at least oneflexible conducting strap interposed between the terminal of one of theterminal bushing for each unit and one of the ends of said respectiveunit.
 2. The truck-mounted multipole vacuum-type circuit interrupter ofclaim 1, including: a pivotally mounted operating lever connected to themovable vertically actuable contact of each vacuum-interrupter unit;and, an insulating operating rod mechanically connected between the freeend of the respective operating lever and the operating mechanism. 3.The combination according to claim 1 wherein each vacuum-typecircuit-interrupter element includes a pair of separable contactsseparated within an evacuated enclosure, at least one contact rodsupporting one of said contacts extending externally of the evacuatedenclosure, and a heat sink comprising a relatively massive contact blocksecured to the external end of said contact rod.
 4. The combinationaccording to claim 3, wherein the contact block is split and adapted forclamping action.
 5. The combination according to claim 1, wherein theflexible mounting means includes a plurality of laterally extendingflexible conducting straps interposed between the terminals of the twoterminal bushings of each interrupter unit and the ends of saidrespective interrupter unit.
 6. At the combination according to claim 1,wherein each vacuum-type circuit interrupter element includes a pair ofseparable contacts separated within an evacuated enclosure, stationaryand movable contact rods extending externally of the evacuatedenclosure, and a pair of heat sinks comprising relatively massivecontact blocks secured to the external ends of said contact rods.
 7. Thecombination according to claim 1, wherein the upper end of each of thevacuum-type interrupter units includes as a part of said flexiblemounting means a pair of laterally extending flexible conducting strapsextending between the upper end of the respective unit and the terminalof the upper terminal bushing for said respective unit.
 8. Thecombination according to claim 3, wherein the flexible mounting meansfor each unit includes a pair of straps disposed on opposite sides ofsaid heat sink.